I got one of the P12 cameras and mounted it behind a telephone jack wall plate. The camera is mounted to the back side of the jack and you can't see the little hole at all. It just looks like a mount to hang a phone on the wall, there's just no phone.
I actually considered getting a cheap wall mount phone and gutting it and mounting it in the phone itself. Just seemed like too much work when the jack itself hides the camera quite well.